Wire bending machine combining a sequential shaping device and a device using a tool plate

ABSTRACT

The invention concerns a machine for automatically shaping components via different types of bending provided in a common plane or different planes. The machine includes a first device for performing a sequential shaping with standard tools by individual bending, and a second device using a tool plate. Both devices are managed by a single digital control. The method for controlling such a machine is characterized in that digital control provides the possibility for producing a blank of a component by individual bending on the first device followed by transfer of the component on the second device for finishing the component. Digital control provides the possibility of shaping one part of the component on the first device and shaping the remaining parts on the second device. The digital control also provides the possibility of using each machine alone and the possibility of using both machines for producing the same component.

CROSS-REFERENCE TO RELATED U.S. APPLICATIONS

Not applicable.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

NAMES OF PARTIES TO A JOINT RESEARCH AGREEMENT

Not applicable.

REFERENCE TO AN APPENDIX SUBMITTED ON COMPACT DISC

Not applicable.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a new wire bending machine and to themethods of controlling such a machine.

2. Description of Related Art Including Information Disclosed Under 37CFR 1.97 and 37 CFR 1.98

At the present time, there are two main types of wire bending machine.

A first type of machine operates sequentially, bend by bend, usingsimple and economical standard tooling, for example tools known as“turntables”, possibly also including a device for rotating the wire sothat bends can be made in different planes.

This type of machine is perfectly adequate for shaping short productionruns of components, both in terms of the quality of the shaping and interms of the profitability and unit cost.

By way of example, patent application EP 0 865 842 describes asequential shaping machine with two bending heads, it being impossiblefor these two heads to operate simultaneously on the same workpiece, itstill being necessary to employ a transfer by gripper in order to changehead and perform flat shaping. This machine has the abovementioneddisadvantages namely that it is adequate only for production runs at lowproduction rates. Furthermore, a sequential shaping machine requires acontrol method capable of programming a geometry.

A second type of automatic bending machine allows a workpiece withseveral bends to be shaped on a tool plate the tools of which areactuated concurrently so as to increase productivity and operate at ahigh production rate.

A machine such as this is numerically controlled and is described inEuropean Patent EP 0 301 972.

More specifically, this relates to a wire bending machine and to themethod of controlling it, which is a method suited to programming themovements of the actuators.

On account of its cost, a machine such as this is suitable only forshaping components in long production runs.

The abovementioned machines do not display optimum profitability whenshaping medium production runs of components because the sequentialmachine operates at too low a production rate, and the machine with atool plate represents too great an investment. In both instances, thisresults in a unit cost that is not optimized for medium production runs.

By way of an illustration of the production problems encountered, if aproduction requires a production rate of a few components per minute,for example of 2 to 3 components per minute, the industrialist willpreferably procure a machine of the sequential type, and if theproduction of a similar component requires a high production rate forexample of 30 to 60 components per minute, a machine with a tool tablewill be procured. By contrast, if a component needs to be produced at anintermediate production rate of, for example, 10 to 12 components perminute, or even of 8 to 30 components per minute, the prior art has nomachine to offer that will suit this need at optimum cost.

There does not currently exist any machine capable of reducing the unitcost when producing medium production runs, and it is thus an objectiveof the present invention to provide a solution to this problem.

BRIEF SUMMARY OF THE INVENTION

The invention consists in a machine for automatically shaping componentsusing various bending operations performed in one and the same plane orin different planes, characterized in that it comprises, in combination,a first device for carrying out sequential shaping bend by bend usingstandard tools, and a second device employing the tool plate, the twodevices being operated using a single numerical control device capableof programming both geometry and actuator movements for a mediumproduction rate.

This really is a combination of two machines because, firstly, the twoshaping techniques have always been poles apart, as the programmingmethods differ from one to the other, one being based on numericalcontrol of the geometry of a component, while the other is based onelectromechanical parameterizing of cams, and because, secondly,production can be optimized when shaping medium production runs,something that was impossible in the prior art, and because, finally, itis possible to omit the need for an actuating arm for changing heads inthe case of flat shaping.

Preferred embodiments of the machine are characterized in that the firstdevice comprises at least one turntable, and/or in that it furthercomprises at least one rotary clamp, and/or that the tool plate can bemounted and actuated in a different plane from the shaping plane of thefirst device, and further comprises a transfer device suited to thechange in plane.

Further, the control method according to the invention is characterizedin that the numerical control device provides the option of creating apart-finished component bend by bend on the first device then oftransferring the component to the second device in order to complete thecomponent, and/or the numerical control device provides the option ofshaping part of the component using the first device and of shaping theremaining part or parts on the second device, and/or the numericalcontrol device provides the option of using each machine on its ownand/or the numerical control device provides the option of employing thetwo machines in order to create the same component.

The invention will be better understood with the aid of the attachedFIGS. 1 and 2 which schematically depict a front view and a view insection along line A-A, of a machine according to an non-limitingalternative form of embodiment of the invention.

A reminder of the principle of a numerical machine according to EuropeanPatent EP 0 301 972 and of its method of operation is also given usingthe attached FIGS. 3 and 4.

The machine depicted in the figures is a combination of a sequentialshaping machine (1) and of a table shaping machine equipped with a toolplate (2), as described in the Patent EP 0 301 972 mentioned in theintroduction.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a schematic view of the wire bending machine of the presentinvention.

FIG. 2 is a cross-sectional view of the wire bending machine of thepresent invention across line A-A of FIG. 1.

FIG. 3 is partial perspective view of the tool plate of the presentinvention.

FIG. 4 is a partial cross-sectional view of the operation of the toolplate in the machine of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

In the example of FIGS. 1 to 2, the sequential machine (1) has standardtools, for example turntables (3, 4) able to move on two axes (x) and(y) to create bends in a plane (x,y), and possibly a rotary clamp (5)when the profile of the component entails bending in a direction that isangled with respect to the plane (x,y).

In the alternative form of FIGS. 1 to 2, the second machine has a table(6) equipped with a tool plate (7), each tool being able to be movedautonomously and being mechanically driven by systems involvingthrough-bolts such as (8) and which are not depicted in detail in thesefigures, each one being controlled by a predetermined program of anumerical control device (9).

As explained in the abovementioned patent, this collection of tools iscapable of creating complex components and/or of creating components ata high production rate.

In the alternative form of embodiment depicted in the figures, the toolplate (7) is positioned in the working plane (x,y) of the first machineand the same wire feed device is able to transfer the wire directly fromthe first to the second machine, and in this case a transfer means cantherefore be omitted.

One and the same numerical control device operates the tools of bothmachines, and is therefore capable of programming both the geometry andthe actuators of the plate, thus allowing the programming steps to becombined with one another.

According to another alternative form of embodiment that has not beendepicted, provision may be made for the shaping planes of the twomachines to be offset from one another in a horizontal direction (z),and where this is done, an arm or some other means needs to be providedin order to transfer the component from the shaping plane (x,y) of thefirst machine to the shaping plane of the tool table (7).

Combining the two machines therefore has the advantage of making iteasier to transfer components and of synchronizing the movements of thetools of the two machines, this synchronization being essential forreducing costs and optimizing manufacture and to allow a single shapingproduction rate on both machines when the shaping steps are spreadacross the two machines.

A component may be shaped according to various combinations ofprogramming which are chosen according to the complexity of the profileto be obtained, according to the investment in special-purpose tooling,or according to the desired production rate:

1) It is, for example, possible to create a part-finished component bendby bend on the first machine (1) then to transfer the component andperform the complex operations and/or to operate at a high productionrate, on the second machine so as to complete the component. Thistechnique is particularly applicable to complex shapes (for examplewhere there are tricky changes in plane, or where closed loops are to becreated). Creating a part-finished component on the first machine makesit possible to reduce the complexity of the tooling of the secondmachine and therefore the overall unit cost.

2) It is equally conceivable for part of the component to be shaped onthe first machine (1) and for the remaining part or parts to befinalized on the second machine (2).

3) It is also possible to use each machine on its own as need be. Forexample, for creating prototypes, only the first machine is used or, forcreating certain components immediately as long production runs, thesecond machine will prove to be the more appropriate one.

4) A solution employing the two machines for creating one and the samecomponent may also be conceived of under the following circumstances:where there is a gradual ramp-up in production rates, where a number ofcomponents are being produced that have a common part (produced on thetool plate) and a specific part (produced on the turntable for example),or for components the design of part of which is not completely set orwhere there are evolutions to a component initially scheduled to beproduced on the tool plate.

Thus, a machine according to the invention displays great flexibility ofuse and is able to respond to all industry requirements for the shapingof wire with the best possible cost/production rate and/or cost/shapingcomplexity optimization, even for medium production runs, something thatcould not be achieved previously.

Using these techniques, the component may be parted off after the firstshaping operation, after transfer between the two machines or after thesecond shaping operation; a first shaping operation on the first machinemay be performed on one component while the final shaping of theprevious component is being performed on the second machine, thusincreasing productivity.

All these shaping operations are rendered possible because the machinesare controlled together, they therefore work together to allow shapingprograms that were not possible when each machine was operatingseparately as in the prior art, making it possible to program a singleshaping production rate for the two machines when the shaping steps arespread across the two machines.

The principle of operation of a machine with a tool plate and the way inwhich it is controlled are recalled here with reference to FIGS. 3 and4.

A machine of this type comprises active means, a work plate, a toolplate, through-bolts and tools, of which the active means, which areautonomous, independent, and secured to the tool plate, actuate leversconnected by through-bolts to the tools mounted on the tool plate, theactive means being mounted on a common translation means via adisengageable means, said active means (60,61,62,63) being moved bybrushless electric motors (70) via ball screws, and the actuating levers(50,51,52,53) that actuate tools (21,22,23,24,25) being connected to thethrough-bolts (30,31,32,33) by connections (40,41,42,43) via one oftheir ends (513) and being connected to the translation means via theirother end (511).

As a preference, a machine of this type is characterized in that thecommon translation means (45) of translating the active means(60,61,62,63) is a rotating screw (45) driven by a motor (90), thedisengageable means being half-nuts in mesh with this same screw.

As a preference, a machine of this type is characterized in that theactive means (60,61,62,63), when in the disengaged position, are fixedto the work plate (1).

Furthermore, the method of controlling it is characterized in that,having studied the movements of the tools, the coordinates of the linkpoints are entered, the characteristics of the active means(60,61,62,63) are stored in memory, and in that the processing unitcalculates the theoretical motor start points so that the tools willoperate concurrently.

As a preference, said method takes account of the inertia of the systemwhen determining the actual start points.

Furthermore, as a preference, the processing unit calculates how thelink points move when the characteristics of the active means(60,61,62,63) and/or one of the values of the coordinates of the linkpoints is or are modified.

Finally, as a preference, the feed starts and feed ends coincide withthe starts and ends of cycles.

A person skilled in the art will be readily able to refer to thecorresponding description in order to reacquaint himself with theworkings of this type of tool plate machine.

1. A machine for automatically shaping components using various bendingoperations performed in at least one plane, said machine comprising: afirst means for carrying out sequential shaping bend by bend usingstandard tools; a second for carrying out sequential shaping bend bybend using a tool plate; and a single numerical control means for boththe first and second means, producing components at a production rate of8 to 30 components per minute.
 2. The machine as claimed in claim 2,wherein the first means comprises at least one turntable.
 3. The machineas claimed in claim 2, wherein the first means further comprises atleast one rotary clamp.
 4. The machine as claimed in claim 1, whereinsaid tool plate is mounted and actuated in a different plane from ashaping plane of the first means, further comprising: a transfer devicesuited to a change in plane from the first means to the second means. 5.The machine as claimed in claim 1, wherein the second means comprises anactive means, a work plate, said tool plate, through-bolts and tools,the active means being autonomous, independent, and secured to the toolplate, said through-bolts connecting actuate levers to the tools mountedon the tool plate, the active means being mounted on a commontranslation means via a disengageable means, said active means havingbrushless electric motors being moveable via ball screws, the actuatinglevers being connected to the through-bolts by connections via one endthereof and being connected to the translation means via an opposite endthereof.
 6. The machine as claimed in claim 5, wherein the commontranslation means is a rotating screw driven by a motor, thedisengageable means being half-nuts in mesh with said rotating screw. 7.The machine as claimed in claim 5, wherein the active means, when in adisengaged position, are fixed to the work plate.
 8. A method ofcontrolling a machine as claimed in claim 1, the method comprising thesteps of: synchronizing the first and second means by the numericalcontrol device.
 9. The method of controlling a machine as claimed inclaim 8, further comprising the step of: providing an option of creatinga part-finished component bend by bend on the first device and thentransferring a component to the second means in order to complete thecomponent.
 10. The method of controlling the machine as claimed in claim8, further comprising the step of: providing an option of shaping partof the component using the first means and shaping the remaining part orparts on the second means.
 11. The method of controlling the machine asclaimed in claim 8, further comprising the step of: providing an optionof using the first means or the second means independently.
 12. Themethod of controlling a machine as claimed in claim 8, furthercomprising the step of: providing an option of employing the first meansand the second means for a single component.